Always set number of slots
Always set number of slots

Relates to #98.

Yubico/yubico-piv-tool,akgood/yubico-piv-tool,Yubico/yubico-piv-tool,Yubico/yubico-piv-tool,akgood/yubico-piv-tool,akgood/yubico-piv-tool,akgood/yubico-piv-tool